Search your domain name
What is a domain name?
Domain names are used in all Internet services (web, email, etc...). They are your identity on the web, and therefore must identify you. Lets take as an example a company called "Bakery Smith" present on the internet:
The address of their website could be: http://www.bakery-smith.com
and one of their email addresses: email@example.com
Everything depends on the common denominator:
bakery-smith.com = the domain name that has been chosen.
Which extension to choose?
Should you choose a generic extension for your domain name such as your-domain.com or your-domain.org? Is it better to choose the extension of a country, such as your-domain.es?
In fact, even if each extension has its own rules and its own cost, this decision is mainly a marketing choice. You must find the right balance between your budget, the image you want to give and the type of services that you offer.
Your business is intended primarily for spanish customers? Take the .es one which has a good image. You are a non-profit organization, consider the .org that reminds of organizations of this type. You can set your imagination free.